Gas lift valve



Nov. 4, 1969 c. R. cANALlzo GAS LIFT VALVE Filed May 22, 1967 4 Sheets-Sheet l INVENTOR Carlos R. Canollzo Nov. 4, 1969 C, R; CANAUZO 3,476,135

GAS LIFT VALVE Filed May 22, 1967 4 Sheets-Sheet "N /Q A@ E.

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Fg.5-A BY Nov. 4, 1969 c. R. cANALlzo 3,476,135

GAS LIFT VALVE' Filed May 22, 1967 4 Sheets-Sheet 4 fafa Fi g. 7- B Fi g 9 INVENTOR Carlo/S R. Canolizo Wj ATTORNEY.;-

United States Patent O Int. Cl. F04f 1/08 U.S. Cl. 137-155 16 Claims ABSTRACT OF THE DISCLOSURE A valve which is connectable in a flow conductor, such as a string of well tubing, for controlling injectionv of gas Vfrom the exterior of the valve into the string of tubing to facilitate production of well fluids through the string of tubing.

This application is a continuation-in-part of application Ser. No. 577,389, filed Sept. 6, 1966.

This invention relates to valves `and more particularly to valves for controlling the admission of gas into a flow conductor to aid movement of fluids through the flow conductor.

An object of the invention is to pro-vide a new and improved valve for removing fluids produced by wells through an inner flow conductor or string of tubing disposed in a well where gas from an annular flow passage between the well and the string of tubing provides lifting power for lightening the well fiuids and transporting them to the surface through the inner well tubing.

Another object is to provide a valve of the type described whose opening and closing is -controlled by the differential between the pressure within the tubing and the pressure of the lift gas exteriorly of the valve,

Still another object is to provide a valve which permits the pressure of the lift gas to be injected into the iiow conductor to be varied without adjustment or change in the valve.

A further object is to provide a valve having a mandrel connectable in a flow conductor to constitute -a section thereof, a sleeve means or assembly disposed about the mandrel and providing an annular longitudinally extending passage thereabout, and a valve means in the passage between a lateral port of the mandrel and the exterior of the valve which is responsive to the differential between the pressures exteriorly of the Valve and within the mandrel for selectively opening the passage when such pressure differential decreases below a first predetermined value and for `closing the passage when the pressure differential increases to a second predetermined value higher than the first value. Y

A further object is to provide a valve wherein the valve means includes a pair of valve assemblies, one controlling the opening of the valve and the other the closing of the Valve.

A still further object is to provide a valve wherein the operation of each of the valve assemblies is responsive to the differential between the pressures in the mandrel and exteriorly of the valve.

A still further object of the invention is to provide a valve of the type described which is provided with a pair of valve means between the mandrel port and the location of communication of the passage with the exterior of the valve wherein one of the valve assemblies when the valve is in its open position moves to its closed position when the differential between the pressures in the mandrel and externally of the valve increases to a first predetermined value to cause the closing of the other or second valve assembly and wherein the second valve as- Patented Nov. 4, 1969 ice sembly causes the valve to open when such differential decreases to a second predetermined Value lower than the rst value.

Additional objects and advantages of the invention will be readily apparent from the reading of the following description of a device constructed in accordance with the invention, and reference to the accompanying drawings thereof, wherein:

FIGURES l-A and I-B are vertical partly sectional views of a valve embodying the invention showing the valve in its open position; FIGURE 1-B being a continuation of FIGURE l-A.

FIGURES 2 and 3 are sectional views taken on lines 2 2 and 3 3, respectively, of FIGURE I-A.

FIGURES 4-A and 4-B are vertical sectional views showing the valve in its closed position; FIGURE 4-B being a continuation of FIGURE /l-A.

FIGURES S-A and 5-B are vertical partly sectional views of a modified form of the valve embodying the invention showing the valve in its open position; FIG- URE 5-B being a continuation of FIGURE 5-A.

FIGURE 6 is a sectional view taken on line 6 6 of FIGURE S-A.

'FIGURES 7-A and 7-B are vertical partly sectional views of another modified form of the valve embodying the invention; FIGURE 7-B being a continuation of FIGURE 7-A.

FIGURE 8 is a sectional view taken on line 8 8 of FIGURE 7-A; and

FIGURE 9 is a perspective view of a component of the valve illustrated in FIGURES 7 and 8.

Referring to FIGURES 1 through 4 of the drawings, the gas lift valve 2t) embodying the invention is connectable in a flow conductor, such as a string of tubing, to constitute a section thereof and includes a mandrel 21 having top and bottom threaded end portions 22 and 23 so that the mandrel may be connected between two sections of the tubing by the usual couplings 24. The mandrel has a longitudinal passage or bore 25 which communicates at its opposite ends with the tubing sections between which the mandrel is connected. A sleeve assembly 26 is disposed about the mandrel and defines with the mandrel an annular chamber or passage 27 which communicates at its top end with the exterior of the valve orifices through 29 of beans 30 threaded in the passages 31 of the top sleeve section 32'and intermediate its ends with the mandrel passage 25 through the mandrel ports 33.

Upward movement of the sleeve assembly on the mandrel is limited by the engagement of the annular top end surface or shoulder of the top section of the sleeve assembly with the downwardly facing shoulder 34 of the mandrel. Downward movement of the sleeve assembly is limited by a nut 35 threaded on the lower end portion 23 of the mandrel above the lower coupling 24. The top annual end surface of the nut engages the bottom annular end surface of the bottom section 36 of the sleeve assembly. The nut may be secured on the mandrel against rotation by a set screw 37.

The sleeve assembly includes a cylinder or chamber section 40 whose upper portion 41 telescopes over the reduced lower end portion 42 of the top sleeve section and whose annular top end surface engages the downwardly facing annular shoulder 46 of the top section. A tubular resilient check valve 48 for preventing upward flow through the passage 27 has an upper portion extending between the portions 41 and 42 of the chamber and top sleeve sections and its lower annular lip portion y49 is adapted to engage an external seal surface 50 of the mandrel below the :bottom end of the top sleeve section. The top sleeve section has a plurality of slots 52 which communicate with an external annular top recess 54 of the mandrel above the seal surface thereof so that Huid may flow downwardly through the passage 27 past the check valve since the orifices 29 of the beans open to the top mandrel recess. The lower portion of the top sleeve section provides a support for the lip portion of the check valve if the pressure in the passage below its lip portion exceeds the pressure thereabove.

The chamber sleeve section 40 has an internally reduced lower portion 61 which is externally reduced as at 66 to provide an annular chamber or space 6/ between the bottom sleeve section and such reduced lower portion of the chamber sleeve section. The top reduced portion 68 of an annular valve member 69 extends into the chamber 67.

An O-ring 71 disposed in an external annular recess of the chamber sleeve section sealingly engages the internal seal surface 72 of the valve member and a similar O- n'ng 74 disposed in an external annular recess of the valve member seals between the valve member and the internal seal surface 75 of the bottom sleeve section. The

upper portion of the bottom sleeve section telescopes over the valve member and the lower portion of the chamber sleeve section, its upward movement being limited by the engagement of its annular top end surface or shoulder with the downwardly facing annular shoulder 78 of the chamber sleeve section.

The bottom sleeve section has a plurality of slots 81 which open to the top end of the chamber 67 above the upper end of the valve member so that the pressure from the exterior of the valve communicated to the upper end of the valve member exerts a downward force on the upwardly facing surfaces of the valve member between the line of sealing engagement of the O-ring 71 with the seal surface 72 and of the O-ring 74 with the seal surface 75.

A spring 84 biases the valve member upwardly toward its open position, its top end portion bearing against the downwardly facing shoulder `85 of a tubular piston 86. The upper end of the piston is telescoped over the externally reduced bottom end portion `87 of the valve member and its top end surface engages the downwardly facing annular shoulder 88 of the valve member. The bottom end of the spring bears against the annular top end surface of a top spacer ring 89 whose bottom end surface in turn rests on the top end surface 90 of the internal annular flange 92 of the bottom sleeve section. The piston is provided with a plurality of circumferentially spaced longitudinally extending slots 94 which permit ow of uids, when the valve member and the piston are in their upper positions, FIGURE l, past a seal 95 disposed about the mandrel above its ports 33 and below the downwardly and outwardly inclined shoulder 97 of a middle external tiange 98 of the mandrel.

The lower portion of the annular resilient seal 95 is disposed in the upward opening internal recess 99 of an annular ring 100 whose lower portion may be crimped at several circumferentially spaced locations, as at 101 into an external annular recess 102 of the mandrel to hold the ring against longitudinal movement on the mandrel. The seal element may be bonded or otherwise secured to the ring. The seal 95 extends upwardly of the top end of the ring and is engagea'ble by the downwardly and outwardly inclined downwardly facing annular seal surface 107 of the valve member when the valve member is in its lower closed position as illustrated in FIGURE 4-A. An O-ring 109 disposed in an external annular recess of the mandrel seals between the mandrel and the Img.

The mandrel is also provided with a pair of external annular recesses adjacent its lower end in which are disposed O-rings 110 which seal between the mandrel and the bottom sleeve section.

In use, the mandrel of the valve is connected n a iiow conductor, such as a string of tubing, to constitute a section thereof and is used to control the flow of lift gas from the annulus between such string of tubing and the well casing into the string of tubing to facilitate or aid in the production of well fluids through the string of tubing. The gas is introduced into the annulus at the surface and the annulus is closed by a packer or other suitable means 4below the valve.

In normal operation of such well, the pressure of the lift gas in the annulus is maintained at a value considerably higher than the pressure in the valve mandrel passage 25 so that when the valve member moves to open position, the lift gas will tiow from the annulus and through the valve into the mandrel passage.

Assuming that the valve is in closed position, it is biased toward closed position by the force of the lift gas pressure exerted on the upwardly facing surfaces of the valve member interiorly of the liue of sealing engagement of the G-ring 74 with the bottom sleeve section since the pressure in the passage 27 above the seal 95 is equal to the pressure exteriorly of the sleeve assembly because no flow is now taking place through the passage 27. The force of the pressure within the passage 27 is also exerted on the downwardly facing surfaces of the valve member interiorly of the line of sealing engagement of the seal 95 with the seal surface 107. The area of this downwardly facing surface is smaller than the combined areas of the upwardly facing surfaces exposed to the lift gas pressure and in the chamber 67 and in the passage 27 and, accordingly, the lift gas exerts a net downward or closing force on the valve member.

The valve member is biased toward open position by the force of the spring 84, which now exerts a relatively great upward force on the valve member, since it is in its most fully compressed condition, and by the force of the uid pressure from the tubing string communicated to the passage 27 below the seal 95 which is exerted on the downwardly facing surface of the valve member 69 between the line of sealing engage'ment of the seal 96 with the seat 107 and the line of sealing engagement of the O-ring 74 with the bottom sleeve section. This pressure is less than the pressure of the lift gas externally of the valve. The valve^ member will then be held in its lower closed position as long as the net downward force exerted therein by the lift gas exceeds the combined upward force exerted therein by the spring and the pressure in the passage of the mandrel.

Assuming that the gas lift pressure in the annulus is maintained constant, the valve will remain in its closed position until the pressure within the passage 25 of the mandrel increases to a predetermined value, as when a column of well fluids rises to a predetermined height above the ports 33 thereof. As the pressure within the mandrel passage 25 rises to a predetermined value which, however, is below the pressure of the lift gas in the annulus, the pressure differential across the valve member is decreased and the valve member is moved upwardly by the spring. As the seat 107 is moved out of engagement with the seal 95, lift gas ows into the top end of the annular passage 27 through the orifices of the beans, moves the lip portion 49 of the check valve 48 out of sealing engagement with the mandrel seal surface 50, and flows downwardly through the passage and the slots 94 to the mandrel ports 33 and thence into the mandrel passage' 25. Due to the restriction provided by the orifices of the beans, the pressure in the passage 27 drops below the pressure exteriorly of the valve. The now lower pressure in the passage 27 exerts a net upward force on an area of the downwardly facing surfaces of the valve member within the lines of sealing engagement of the O-rings 71 and 74 with the seal surfaces 72 and 75, respectively, which is equal to the area of the upwardly facing surfaces of the valve member in the chamber 67, also within the lines of sealing engagement of the O-ring 71 and 74, exposed to the higher pressure in the annulus. As a result the pressure differential across the valve member when the valve member is in open position biases the valve member toward closed position and the valve member is held in open position by the spring 84 which, however, now exerts a smaller upward force on the valve member than that exerted thereby when the valve member was in closedpposition since it is now in less compressed condition, the spring being a high rate spring whose force resisting compression increases as the degree of its compression.

The pressure in the mandrel passage 25 drops as the well liquids are expelled from the tubing string at the surface and as the pressure differential across the valve member thus increases to a predetermined Value, the downward force exerted on the valve member by the lift gas in the chamber 67 is effective to move the valve member to closed position.

As the valve member moves toward its closed position, against the force exerted by the spring and the pressure in the passage 27, and its seat surface 107 moves past the surface 97 of the' mandrel flange 98, the effective orifice of the passage decreases causing a further decrease in the pressure in the mandrel be'low the seal, thus quickly increasing the pressure differential across the valve member so that the valve will close with a snap action.

Since the upward force exerted by the spring 84 increases as it is compressed, it exe'rts the least upward force when the valve is in its uppermost open position and since the lift gas pressure is exerted across a greater effective area of the upwardly facing surfaces of the valve member 69 when the valve member is in closed position than when it is in open position, the valve member will close at a lower pressure differential between the exterior of the valve and the mandrel passage 25 than the value of such pressure differential at which it will move from closed to open position. Closing of the valve at such lower pressure differential between the annulus or lift gas pressure and the mandrel passage pressure is desirable to conserve lift gas. For example, if the valve is used to intermittently produce slugs or columns of well liquids, as each slug or column of well liquids begins to flow from the upper end of such string of tubing, it is desirable to close the valve to prevent further flow of lift gas into the string of tubing since the expansion of the gas previously introduced will be effective to complete the ejection of such slug of the well liquids.

It will be apparent that the pressure differential at which the valve moves to its closed position may be varied by varying the effective combined orifice of the beans or the force' exerted on the valve member by the spring 84. It will be apparent that the annulus pressure of the lift gas may be adjusted to any desired value, as long as it is kept higher than the pressure within the mandrel passage. The height of the column of liquids in such tubing string above the mandrel ports 33 at which the valve will open increases if the annulus pressure is raised to a higher value.

It will now be apparent that the valve member when in closed position is biased toward closed position by the force exerted thereon due' to the pressure differential between the mandrel passage 25 and the exterior of the valve and is biased toward open position by the spring 84 and that when the pressure differential drops to a predetermined value at which the upward force exerted by the spring on the valve member exceeds the downward force thereon exerted due to such pressure differential, the valve member will be moved to its upper open position.

Referring now particularly to FIGURES 5 and 6 of the drawing, the valve 200 embodying the invention, which also closes at a lower pressure differential between the lift gas pressure and the pressure within the valve than such pressure differential at which it opens, includes a mandrel 201 which has top and bottom threaded portions 202 so that it may be connected by means of the usual coupling collars 204 and 205 in a flow conductor, such as a string of well tubing, to constitute a section thereof. A sleeve assembly 208 disposed about the mandrel intermediate its ends provides with the mandrel an annular passage 209 to which open the lateral ports 210 of the mandrel which communicate with the longitudinal passage 212 of the mandrel. The passage 210 is closed at its lower end while its upper end is in communication with the exterior of the valve through the orifices 214 of beans 215 threaded in apertures 217 of a top section 218 of the sleeve assembly.

The sleeve assembly includes an upper chamber section 221, an upper spacer section 222, a lower chamber section 223, a lower spacer section 224 and a bottom or ring section 225. Upward movement of the sleeve assembly on the mandrel is limited by the engagement of the annular top end surface of the top sleeve section with the downwardly facing annular shoulder 228 of lthe mandrel spaced above an external annular top recess 229 thereof, the orifices 214 of the beans opening to the top recess. The upper chamber section 221 telescopes over a reduced portion 231 of the top section and its upward movement relative thereto is limited by the engagement of its top annular shoulder with the downwardly facing annular shoulder 232 of the top section. The top section is further reduced along its lower portion, as at 233, so that the top section and the upper chamber section provide an annular downwardly opening recess in which is disposed the upper portion of a tubular check valve 236 which may be bonded to the top section and also held against downward displacement by the upwardly facing annular shoulder 237 of the upper chamber section.

The lower portion of the top section extends downwardly of the lower end of the top mandrel recess 229 and is provided with slots 239 which provide communication with the recess 229. The lower portion of the top section provides a support for the lower lip portion 240 of the check valve, which is adapted to sealingly engage the seal surface 242 of the mandrel located immediately below the recess 229 if the check valve is deformed inwardly when the pressure in the passage 209' therebelow increases above that externally of the valve.

The lower reduced end portion 244 of the upper chamber sleeve section and the upper end portion of the upper spacer section 222 provide an annular chamber 245 therebetween in which is slidable the upper reduced portion 246 of an annular upper valve member 247. The upper spacer sleeve section 222 is provided with a plurality of slots 248 which communicate with the chamber 245. Upward movement of the upper spacer section on the upper chamber section is limited by the engagement of the top annular end surface of the upper spacer section with the downwardly facing annular shoulder 249 of the upper chamber section. An external support flange 250 of the mandrel is aligned with the bottom end portion 244 of the upper chamber section and has slots 250a which constitute portions of the passage 209. The lower reduced portion 244 of the upper chamber section is provided with an external annular recess in which is disposed an O-ring 251 which sealingly engages the internal seal surface of lche top portion 246 of the valve member. The valve member in turn has an external annular recess in which is disposed an O-ring 253 which engages the internal seal surface of the upper spacer section 222.

The upper valve member has a downwardly and outwardly sloping seat 255 which is adapted to engage the resilient annular seal 256 supported on the mandrel by a ring 258. The ring 258 has an internal upwardly opening recess 259 in which the lower portion of the seal is received. An O-ring 261 disposed in an external annular recess of the mandrel seals between the mandrel and the ring 258. The lower reduced portion 262 of the ring extends over an external latch recess 264 of the mandrel and is crimped or deformed inwardly at circumferentially spaced locations therealong to hold the ring against movement on the mandrel. The valve member when its seat 255 engages the seal 256 does not completely close the passage 209 since the seat is provided with grooves 266 which provide a passage of restricted orifice between the ring 258 and the valve member.

The valve member 247 is biased upwardly toward its opened position by a spring 268 acting thereon by means of a tubular upper piston 269 whose upper end telescopes over the lower reduced portion 271 of the upper valve member. Upward movement of the upper piston relative to the upper valve member is limited by the engagement of its top annular end surface with the downwardly facing annular shoulder 273 of the valve member. The piston is provided with a plurality of circumferentially spaced longitudinal slots 275 to facilitate fluid flow in the passage 209 pass the ring 258.

The upper end of the spring 268 bears against the bottom end surface 278 of the piston and its lower end portion engages the top surface of a spacer ring 279 whose bottom surface rests on the top annular shoulder or surface of the lower chamber sleeve section 223. The lower chamber section has an upper reduced portion 281 which telescopes into the lower end of the upper spacer section and the two sleeve sections are rigidly secured to one another in seal tight relationship by a weld 283.

It will be apparent that the upper valve member, the seal 257, the piston 269, the spring 268 and the three upper sleeve sections constitute an upper valve assembly A which, as will be explained below, controls the closing of the valve and causes it to close at a predetermined pressure differential between the exterior of the valve and the passage 212 of the mandrel which is lower than the pressure differential at which the valve opens, the opening of the valve being controlled by a lower similar valve assembly B.

The mandrel at the location of the lower chamber section 223 is provided with an external annular flange 285 which engages the internal surface thereof, the flange having grooves 286 to permit fluid flow therepast.

The lower reduced portion 288 of the lower chamber section and the upper end portion of the lower spacer sleeve section 224 define an annular chamber 289 into which extends slidably the upper section 291 of the lower valve member 292 of the lower valve assembly. The lower sleeve section has slots 294 which open to the chamber 289 at its upper end. O-rings 296 and 297 disposed in external annular recesses of the lower chamber section and the lower valve member, respectively, seal between the lower chamber section and the valve member and between the valve member and the lower sleeve section. The lower valve member has an annular downwardly and outwardly extending seat surface 299 which is engageable with a resilient seal 301 when the valve member is moved to its lower position to close the passage 209 above the mandrel ports 210. The seal 301 is disposed in an upwardly opening internal recess 302 of a ring 303 whose lower reduced end portion extends over an external annular recess 304 of the mandrel and has portions thereof crimped or deformed inwardly thereinto to limit downward movement of the ring on the mandrel.

The lower valve member 292 is biased toward its upper open position by a lower spring 308 and a lower tubular piston 309. The upper end portion of the lower piston is telescoped over a lower end portion of reduced external diameter of the lower valve member, its upward movement relative to the valve member being limited by the engagement of its top annular end surface with the downwardly facing shoulder 310 of the lower valve member. The piston has a plurality of longitudinal slots 312 to facilitate fluid flow past the seal and the ring. The upper end of the spring 308 bears against the annular bottom end shoulder or surface 312 of the piston while its lower end bears against the top annular end shoulder or surface of a spacer ring 313 which rests on the top surface of the bottom ring section 22S. The bottom section 225 of the sleeve assembly has an upper reduced portion 316 which telescopes into the lower end of the lower spacer section 224 and is secured thereto in seal tight relationship in any suitable manner, as by a weld 318. The seal assembly is held against downward movement on the mandrel by a nut 320 threaded on the lower threaded portion 203 of the mandrel. O-rings 321 disposed in external annular recesses of the mandrel seal between the bottom sleeve section 22S and the mandrel and thus close the bottom end of the passage or cylindrical space 209.

In use, the spring 268 and its spacer ring are so chosen that it exerts a smaller upward force on the upper piston 269 and the upper valve member 247 than the force with which the spring 308 biases the lower piston and lower valve member 292 upwardly. For example, the upper spring 268 may exert an upward force of pounds on the upper valve member when the upper valve member is in open position while the lower spring 308 may exert an upward force of 200 pounds on the lower valve member when it is in open position. Assuming that the valve has just moved to its open position illustrated in FIGURE 5, and that the pressure of the lift gas externally of the valve is maintained constant, lift gas flows through the passage 209 to the ports of the mandrel. As the lift gas enters into the mandrel passage 212, it lightens and lifts a column of well liquids in the string of tubing to the surface. The upper valve member is now biased downward toward closed position by the pressure exteriorly of the sleeve assembly and is biased upwardly by the spring 268 and the fluid pressure in the passage 209 below the upper valve member which, due to the restriction offered by the beans 215, is lower than the pressure exteriorly of the valve. This pressure differential exerts a downward force on the valve member which, however, is more than balanced by the upward force exerted by the spring 268.

Similarly, the pressure differential between the passage 209 and the exterior of the sleeve assembly acting across the lower valve member 292 exerts a downward force on the lower valve member which is biased against downward movement by the force of the spring 308. As the slug or column of well liquids moves to the surface and begins to ow out of the upper end of the string of tubing, the pressure at the ports 210 decreases and when it decreases to such extent that the increased pressure differential across the upper valve member 247 exerts a downward force on the upper valve member sufficiently great to overcome the force exerted by the spring 268, the upper valve member moves downwardly and engages its seal 256. Once the upper valve member engages its seal 256, the pressure in the passage or space 209 below the seal 256 decreases very rapidly since very little fluid can ow through the restricted orifices or recesses 266 in the seat 255 of the upper valve member and, as a result, the pressure in the passage 209 therebelow and in the passage 212 of the mandrel decreases rapidly. The pressure differential across the lower valve member 292 thus now increases very rapidly so that the force of the spring 308 is overcome and the lower valve member moves downwardly and closes the passage or space 209 above the seal 301 and the ports 210.

The upper valve member is moved to its lower closed position `before the lower valve member is moved to its lower closed position, since the two valve members are of substantially identical configurations and the areas thereof exposed to the pressures in the passage and the chambers 245 and 289 are substantially equal in area, and since the upward force of the upper spring 268 is smaller than the upward force of the lower spring 308.

The pressure differential across the upper valve member which exerts a downward force on the upper valve member now slowly decreases as the gas from the exterior flows downwardly through the small orifices of the grooves 266 in the seat 255 of the upper valve member and, as such pressure differential decreases to such a low value that its force on the upper valve member is overcome by the force of the vspring 268, the upper valve member is moved to its upper open position by the spring.

ment with the mandrel seal surface 434. As the column of liquids fiows out of the upper end of the string of tubing, the pressure in the mandrel at the ports 406 drops and as it drops to a value where the force of the pressure differential across the tubular body is sufficient to overcome the biasing force of the tubular element 426, the tubular body is contracted and the seal ring 433 engages the seal surface 434, thus closing the passage 407 between the beans and the lower valve member 292a. As the lift gas cannot fiow downwardly in the passage 407 past the upper valve assembly A, the pressure in the mandrel at the ports 406 decreases rapidly and thus greatly increases the pressure differential across the lower valve member 292a and causes it to move downwardly against the force exerted by the spring 3080. Once the valve assembly A is moved to its closed position, the pressure -within the passage 407 above the valve I407 increases, as fluid continues to flow through the orifices into the top end of the passage, thus decreasing the pressure differential across the tubular body 425 which is moved back to its radially expanded open position illustrated in FIGURE 4 by the force of its tubular element 426, and pressure in the portion of the passage 407 above the line of sealing engagement of the seal 301a with the seal surface 299a of the lower valve member now equalizes with the pressure exteriorly of the valve. The lower valve member 292m will now remain in its lower closed position, being biased thereto by the pressure differential thereacross, until the column of liquids is expelled from the string of tubing and the pressure within the mandrel at the ports 406 again rises as another column of liquids accumulates in theY string of tubing above the ports 406. When the force of the pressure differential across the valve member decreases to such degree that its downward force exerted on the lower valve member becomes less than the upward kforce exerted thereon by the spring 308a the valve member will move to its upper open position and will again remain open until the upper valve assembly A again causes its closure.

It will now be apparent that each of the different forms of the valve embodying the invention operates in response to the pressure differential between the fluid pressure in the mandrel and the lift gas pressure exterior of the valve and opens at a higher value of such pressure differential than the value thereof at which it closes to provide for optimum efficiency of operation of the well installation in which it is connected.

It will also be apparent that each of the described and illustrated valves embodying the invention will operate properly regardless of variations in the pressure of the lift gas, as long as the lift gas pressure is maintained above a value predetermined by the force exerted by the means biasing the valve toward open position, to provide for great fiexibility and adjustability of the operating conditions of the well installation in which the valve is connected.

What is claimed and desired to be secured by Letters Patent is:

1. A valve including: a tubular mandrel connectable in a flow conductor to constitute a section thereof; means disposed on said mandrel and defining with said mandrel an annular passage about said mandrel, said mandrel having port means providing communication between the interior of said mandrel and said passage, said valve having restricted inlet means providing communication between the exterior of said valve and said passage at a location spaced from said port means; valve means for closing said passage between said port means and said inlet means, said valve means having surfaces exposed to the pressure from the exterior of said valve, tothe pressure in said passage between said valve means and said inlet means and to the pressure in said passage between said port means; biasing means biasing said valve means toward open position; and said valve means, said valve means when in closed position being biased toward closed position by the force of uid pressure from exteriorly of said valve and in said passage between said inlet means and said valve means and being biased toward open position by said biasing means and by the force of fluid pressure in said passage between said port means and said valve means, said valve means when in open position being biased toward closed position by the fluid pressure from exteriorly of said valve andtowardV open position by said biasing means and by the force of fluid pressure in said passage, the pressure of fluids acting on the surfaces of said valve means exposed to the pressures in the passage and from the exterior of the valve causing said valve means to move from open to closed position when the differential between the pressures in the interior of the mandrel and exterior of the valve exceeds a first value and causing said valve means to move from closed to open'position when said differential decreases to a second value less than said first value.

2. The valve of claim 1, wherein said port means has a greater effective orifice than said inlet means whereby the pressure within said passage decreases when said valve moves to its open position and fluid is flowing from the exterior of the valve through said passage to said port means.

3. The valve of claim 2, wherein said means providing said passage has an annular chamber intermediate its ends open to opposite ends to said passage and of the exterior of the valve; an annular valve member movable in said chamber; and seal means on said mandrel engageable by said valve member to close said passage when said valve member is moved to closed position.

4. The valve of claim 3, wherein said valve member and said seal means when valve member is in closed position cause the press-ure in said passage between said valve member and said inlet means to exert a force biasing the valve member to its closed position.

5. The valve of claim 4, wherein, the lforce exerted by said `biasing means on said valve member increases as the valve moves from its open toward its closed position.

6. A -valve including: a tubular mandrel cOnnectable in a flow conductor to constitute a section thereof; means disposed on said mandrel and defining with said mandrel a passage about said mandrel, said mandrel having port means providing communication between the interior of ksaid mandrel and said passage, said valve having inlet means providing communication between the exterior of said valve and said passage at a location spaced from said port means; and valve means for closing said passage between said port means and said inlet means, said valve means comprising a first valve means and a second valve means, said first valve means being movable -between an open position and closed position, and being disposed in said passage between said port Imeans and said second valve means, said first valve means when in closed position being responsive to a first pressure differential between the interior of said mandrel and the exterior of said valve and moving to open position when said first pressure differential decreases to a first predetermined value, said second valve means being disposed in said passage between said inlet means andv said first valve means and being responsive to a second pressure differential between the exterior of said valve and said passage and moving from open position to closed position when said second pressure differential increases to a second predetermined value higher than said first predetermined value.

7. The valve of claim 6, wherein said port means has a greater effective orifice than said inlet means whereby the pressure within said passage `decreases when said first and second valve means are open and fiuid flow takes place through the passage from said inlet means to said port means.

8. The valve of claim 7, andfirst biasing means biasing said first valve means to open position and second valve means biasing said second valve means to open position with a force lower than that with which said The increase in the pressure in the passage 209 above the seal 301 does not materially affect the force with which the lower valve member 292 is biased toward its lower closed position by the pressure differential across the lower valve member since, when the lower valve member is in its closed position, the area of the downwardly facing surfaces within the line of sealing engagement of the seal 301 with the seat 299 is substantially equal to the area of upwardly facingy surfaces of the lo'wer valve member extending inwardly of the line of sealing engagement of the O-ring 296 with the valve member. The lower valve member is thus held in its closed position by the force of the pressure differential between the pressure of the lift gas in the chamber 289 and the well fluid pressure in the passage 209 below the seal 301 which is now partly oflset by the upward force exerted by the spring 308. The lower valve member will remain closed as the column of well liquids is discharged from the surface and the pressure in the string of tubing drops.

As a column of well liquids will then again accumulate and rise in the string of tubing above the ports 210, the pressure differential across the lower valve member decreases until the downward force exerted thereby on the valve member decreases to the point where the force of the spring 308 is effective to move the lower valve member upwardly to open position.

The above described sequence of operation of the valve 200 will be repeated each time a column of liquids rises to a predetermined height in the string of tubing above the mandrel ports.

It will now be apparent that the upper valve assembly A controls the closing of the valve while the lower valve assembly B controls the opening.

It will further be seen that the openin g and closing pressure differentials can be varied as desired by varying the force with which the springs of the two valve assemblies bias their valve members toward their closed positions, either by changing, adding or removing the spacer rings, such as the spacer rings 279 or 313, by using springs of different strengths, or by substituting beans of different orifices.

It will further be apparent that the pressure of the lift gas in the well about the string of tubing may be varied as required by the particular characteristics of a particular well to provide for optimum well fluid production with minimum expenditure of lift gas since the operation of the valve is dependent on the differential between the pressure of the lift gas and the pressure in the string of tubing at the mandrel of the valve, and the pressure of the lift gas can be varied as desired as long as it is maintained higher than the pressure in the mandrel. Any increase in the lift gas pressure will require a higher pressure or column of well fluid in the string of tubing above the mandrel port 210 or higher spring pressure to cause opening of the valve.

Referring now to FIGURES 7 through 9 of the drawings, the valve 400 differs from the valve 200 principally in having an upper valve assembly A different in structure Ifrom the valve assembly A of the valve 200. The valve 400 embodying the invention includes a mandrel 401 connectable in a flow conductor, such as a string of tubing, by means of its opposite threaded end portions 402 and 403 and the usual couplings 404 to constitute a section thereof. The mandrel has a plurality of lateral ports 406 intermediate its ends which open from its bore to a cylindrical passage or space 407 provided by the mandrel and a sleeve assembly 408 mounted on the mandrel. The sleeve assembly includes a top section 410 having a plurality of threaded bores 412 in which are threaded beans 413 which provide restricted orifices l414.. The orifices open into the upper end of the passage 407 whose extreme upper end portion is provided by an external annular top recess 416 of the mandrel.

A check valve 418 is secured between the top section and a valve retainer section `420 of the sleeve assembly. The check valve has a lower lip portion 421 which is engageable with the annular external seal surface 422 of the mandrel located below its top recess. The top section has a reduced section 423 which extends below the lower end of the top recess and is provided with slots 424 which communicate with the recess 416.

The upper valve assembly has a tubular body 425 which includes a tubular resilient metal member 426 having upper enlarged portion 427, a lower reduced portion 428, and an intermediate portion 429 which extends radially outwardly and upwardly from the top end of the lower portion to the bottom end of the upper portion. The tubular member 426 has a plurality of circumferentially spaced longitudinal slots 430 to increase its flexibility. The valve assembly also includes a resilient sleeve 432 of rubber or the like molded or otherwise secured to the exterior of the tubular element and an inner resilient ring 433 also of rubber or the like preferably integral with the sleeve. The seal ring has an arcuate surface which is adapted to sealingly engage a seal surface 434 of the mandrel between the external annular flanges 436 and 437 of the mandrel. The flanges 436 and 437 have longitudinal slots 438 and 439, respectively, which provide passages past the lower portion of the retainer sleeve section 420 and of the cylinder sleeve section 440. The upper end portion of the tubular body 425 extends between the reduced portion 441 of the valve retainer section 420 and the upper reduced portion 444 of the chamber section 440. The resilient sleeve member seal between the sleeve sections 420 and 440. The lower reduced portion 441 of the retainer section may have a downwardly and inwardly sloping surface 446 to support the upper portion of the tubular body when it is moved to its inner retracted position. Similarly, the lower end portion of the tubular body 425 is compressed between the mandrel flange 437 and the lower portion 449 of decreased internal diameter of the chamber section 440. The resilient metal member 426 biases the intermediate portion of the tubular body 425 radially outwardly to a position wherein the inner seal ring 433 is out of engagement with the mandrel seal surface `434. The pressure exteriorly of the sleeve assembly is communicated to the exterior of the tubular body through the ports 452 in the chamber section which open to an annular chamber 453 between the tubular body and the upper chamber section.

The lower valve assembly B of the valve 400 being identical in structure to the lower valve assembly B of the valve 200, its elements have been provided with the same reference numerals, to which the subscript a has been added, as the corresponding elements of the valve 200. The force with which the tubular metal member 426 biases the tubular body toward its open position is less than the force with which the spring 308a biases its valve member 292a to closed position so that, as in the case of the valve 200, the upper valve assembly A will control closing of the valve 400 and cause it to close when the pressure differential between the mandrel passage and the exterior of the valve is less than the pressure differential required to cause the valve assembly B, which controls opening of the valve 400, to open the valve.

Assuming now that the valve assemblies A and B of the valve 400 have just moved to their open positions, lift gas is flowing into the top end of the passage 407, downwardly past the check valve and the valve assemblies A and B, to the lateral ports 406 of the mandrel and thence into the longitudinal passage of the mandrel to lift a column of well liquids present in the string of tubing in which the mandrel is connected. Due to the restriction provided by the orifices of the beans, the pressure in the passage 407 decreases below the pressure exteriorly of the valve when the lower valve assembly B opens, so that a pressure differential is now present across the tubular body 425 which tends to contract the middle portion of the tubular body and move its seal ring 433 into engage- 13 first biasing means biases said rst valve means toward open position.

9. The valve of claim 8, wherein said second valve means when in closed position has means providing for restricted fluid ow therepast in said passage whereby the pressure differential across said second valve means tends to equalize after said first valve means moves to closed position to permit said second biasing means to move said second valve means to open position after said first valve means moves to closed position.

10. The valve of claim 8, wherein each of said rst and second valve means includes a seal mounted on said mandrel, and a valve member mounted for limited longitudinal movement in said means disposed on said mandrel, said valve member being movable to position engaging said seal to close said passage.

11. The valve of claim 10, wherein each of said valve members has a irst surface exposed to the pressure exterior of said means disposed on said mandrel for carrying the pressure from the exterior of said means to exert a foroe on said rst surface tending to move said valve member to closed position and a second surface exposed to the pressure 4in said passage for causing the pressure in said passage to exert a force on said second surface tending to move said valve member to open position.

12. The valve of claim 11, wherein said valve member of said second valve means has means providing a restricted passage past said seal of said second valve means when said valve member of said second valve means is in closed position and engaging said seal of said second valve means.

13. The valve of claim 8, wherein said first valve means includes a seal on said mandrel and a valve member mounted lfor limited longitudinal movement on said mandrel, said valve member being movable to position engaging said seal to close said passage.

14. The valve of claim 13, wherein said valve member has a rst surface exposed to the pressure exteriorly of said means disposed on said mandrel for causing the pressure from the exterior of said means to exert a force on said rst surface tending to move said valve member t0 closed position and a second surface exposed to the pressure in said passage cau-sing the pressure in said passage communicated thereto from said mandrel through said port means when said valve member is in closed position to exert a force on said valve member tending to move said valve member to open position.

15. The valve of claim 14, wherein said second valve means comprises a second valve member having a first surface exposed to the pressure from the exterior of said means disposed on said mandrel for causing the pressure 4from the exterior of said means to exert a force on said second valve member tending to move said second valve member to closed position and a second surface exposed to the pressure in said passage communicated thereto through said inlet means for causing the pressure in the passage to exert a force on said second valve member tending to move said valve member to open position.

16. The valve of claim 15, wherein said second valve member comprises a resilient tubular member disposed about said mandrel and secured at opposite ends to said means, said tubular means having internal seal means engageable with said mandrel for closing said passage.

References Cited UNITED STATES PATENTS 3,223,109 12/1965 Cummings 137-155 ALAN COHAN, Primary Examiner U.S. Cl. X.R. 

